Polyvinyl acetate plasticized with succinimide



United States Patent Ofiiice 3,316,196 POLYVINYL ACETATE PLASTICIZEDWITH SUCCINIMIDE William F. Hill, Jr., South Charleston, W. Van,assignor to Union Carbide Corporation, a corporation of New York NoDrawing. Original application Oct. 9, 1958, Ser. No. 766,1 88. Dividedand this application May 4, 1962,

Ser. No. 192,330

3 Claims. (Cl. 260-496) This application is 766,188, filed Oct. 9, nowabandoned.

This invention relates to novel polyvinyl acetate compositions and tomethods for their preparation. In a particular aspect, this inventionrelates to plasticized plyvinyl acetate compositions which are capableof forming continuous, flexible coatings on substrates at roomtemperature when applied as aqueous dispersions.

Polyvinyl acetate aqueous dispersions find wide commercial applicationas inexpensive resin bases for paints, adhesives, sizes, caulkingcompounds, paper-coatings, and the like. When polyvinyl acetatedispersions are applied to substrates at room temperature, they formnonhomogeneous films which must be baked to make them continuous andflexible or they form homogeneous films that are lacking in strength.Solvents and filming aids such as dibutyl phthalate can be employed topromote good film formation but they sometimes tend to coagulate thedispersed polyvinyl acetate, and they volatilize out of applied coatingsover a period of time. Further, it is inconvenient to transport andstorecommercial polyvinyl acetate aqueous dispersions in their latex formbecause latex materials require certain precautions in storing andhandling, e.g., bulk storage tanks and drums and circulating pumps mustbe stainless steel. or have a baked phenolic resin lining or glasslining because latices tend to coagulate when they contact steel orbrass. Also, latices are not able to withstand prolonged heating andrepeated freeze-thaw cycles.

It is an object of this invention to provide plasticized polyvinylacetate compositions which can be handled and stored as dry-blendswithout being affected by adverse conditions and which can be readilydispersed in an aqueous vehicle.

It is another object of this invention to provide aqueous polyvinylacetate dispersion compositions which form continuous, flexible coatingson substrates atroorn temperature.

Other objects and advantages of this invention will become apparent fromthe accompanying description and disclosure.

Accordingly, this invention provides compositions comprising polyvinylacetate and a water-soluble organic compound having a melting pointabove about 35 C. selected from the group consisting of aliphatic andaromatic carboxylic acids, amides, imides, carbamates and nitriles.

By the term water-soluble compound is meant a solid compound having asolubility of at least 0.1 part by weight in 100 parts of water at atemperature in the range between about C. to 35 C. The water-solublecompounds preferred are those which have a solubility of at least 4parts by weight in 100 parts of water at temperatures around roomtemperature (about C.). The water-soluble, solid compounds act as aplasticizer or semi-solvent for polyvinyl acetate in aqueous dis persioncompositions.

The water-soluble compounds, i.e., solid plasticizers, having a meltingpoint above about C. contemplated to be employed in the compositionsinclude unsaturated monobasic carboxylic acids such as crotonic acid,di-

a division of application Ser. No. 1958, by William P. Hill, Jr., and

3,316,196 Patented Apr. 25, 1967 methylacrylic acid, angelic acid,tiglic acid, maudelic. acid, sorbic acid, and the like, containingbetween four and about eight carbon atoms; saturated dibasic carboxylicacids such as malonic acid, glutaric acid, glutamic acid, axelaic acid,malic acid, tartaric acid, and the like, contining between three andabout ten carbon atoms; unsaturated dibasic carboxylic acids such asmaleic acid, fumaric acid, mesaconic acid, citraconic acid, glutaconicacid, itaconic acid, and the like, containing between four and about tencarbon atoms; tribasic carboxylic acids such as tricarballylic acid,aconitic acid, citric acid, 1,2,4-butanecarboxylic acid, and the like,containing between five and about ten carbon atoms; monoamides such asacetamide, acrylamide, crotonamide, methylethylacets amide,isovaleramide, heptamide, and the like, containing between two and abouteight carbon atoms; polyamides such as succinamide, maleamide,adipamide, and the like, containing between three and about eight carbonatoms; saturated and unsaturated imides such as succinimide, maleimide,parabanic acid, and the like, containing between four and about eightcarbon atoms; carbamates such as methyl carbamate, ethyl carbamate,n-propyl carbamate, ethyl phenyl carbamate, and the like, containingbetween two and about ten carbon atoms; and nitriles such asmalonitrile, succinonitrile, tricyanoethyl amine, and the like,containing between three and about ten carbon atoms.

v The particularly preferred water-soluble, solid plasticizers of theabove classes to be employed in the compositions of this invention aremalonic acid, acetamide, succinimide, succinonitrile, ethyl carbamateand acrylamide. These preferred solid plasticizers are inexpensive andreadily available and produce excellent results.

The polyvinyl acetate resins which are commercially available under avariety of trade names can be employed as the resinous component of thecompositions. The polyvinyl acetate resins preferred are those whichhave a. resin grade value in the range between about 2 and 10, and arein a finely-divided state with a particle size between about 0.2, and 20By the term resin grade value pressed as viscosity in centipoises finedby the following equation:

is meant a value ex- (1 cps.) which is derefers to the followingproportion of components:

Parts Resin 2 Water 5 Dimethylformamide 93 Polyvinyl acetate resins canbe conveniently produced in aqueous emulsion systems by polymerizingvinyl acetate at a temperature between about 50 C. and C. in thepresence of a peroxide catalyst such as acetyl peroxide, benzoylperoxide or hydrogen peroxide. Emulsifying agents and stabilizing agentsare usually included in the polymerization systems, as well as variousother materials such as formic acid, sodium vinyl sulfonate, laurylmercaptan, sodium bisulfite, and the like, which serve as initiators ormodifiers.

The preparation of polyvinyl acetate in emulsion polymerization systemsis especially advantageous as compared to solution systems because theaqueous dispersed resin product mixtures that are recovered can beemployed directly to prepare compositions of this invention. Thesecompositions are prepared by the simple expediency of mixing togetherthe aqueous dispersion of polyvinyl acetate with ethyl canbamate or oneof the other members of the previously described group of water-soluble,solid plasticizers having a melting point above about 35 C.

Aqueous dispersions of polyvinyl acetate produced in emulsionpolymerization systems are also useful in the practice of this inventionfor providing solid compositions which can be conveniently stored andhandled. The polyvinyl acetate aqueous dispersions are spray-dried andthen mixed with one of the solid plasticizers described above. Theseplasticized solid, polyvinyl acetate compositions are readilydispersable in water, and the resulting dispersions form continuous,flexible films when applied to substrates at room temperature, e.g., ata temperature of about 25 C., in the same manner as the compositionsprepared by mixing a solid plasticizer with emulsion polymerizationlatex product mixtures.

The quantity of water-solubleorganic compounds employed in thecompositions can very over a wide weight range depending on such factorsas the particle size of the polyvinyl acetate, the degree of solubilityof the particular plasticizer in water and the degree of flexibilitydesired in the product. Generally, a quantity of water-solubleplasticizer is employed which is in the range between about 5 and 60percent or more by weight, based on the weight of polyvinyl acetate inthe compositions. The preferred compositions for obtaining relativelytack-free films are prepared with between about 5 and 30 percent byweight of water-soluble plasticizer based on the weight of polyvinylacetate. The weight of polyvinyl acetate resin contained in aqueousdispersions can be varied over a broad range depending on the particlesize of the resin and on the dispersion viscosity desired for aparticular application, and other such considerations. Generally, thedispersed polyvinyl acetate will vary between about 40 and 60 percent byweight, based on the total weight of the composition.

One of the commercial polyvinyl acetate resins (Bakelite, Vinyl ResinLatex WC-130) useful for the preparation of the compositions of thisinvention has as typical properties a total solids content (percent) of58511.5, a viscosity, centipoise (Brookfield) of 1,500 to 2,500, a pH of45:05, a specific gravity of 1.104, and an average weight per gallon(lbs.) of 9.2.

The compositions of this invention can contain pigments and fillers orthey can be utilized without such materials to produce clear coatings ona variety of substrates. The compositions can be premixed with drypigments and fillers and subsequently mixed with water to form valuablecoating materials. The compositions can be applied by all theconventional methods such as spraying, dipping, brushing, roll-coating,or knife-coating. The compositions find utility in exterior and interiorhouse paints for wood and masonry surfaces, textile coatings and sizes,paper coatings, beater additives in papermaking, adhesives, caulking andpatching compounds, joint cements for dry-wall construction, and othersuch uses.

An outstanding advantage of the compositions of this invention is thatthey form continuous, flexible films when applied with an aqueousvehicle at room temperature. Without the benefit of the water-soluble,solid plasticizers described herein, aqueous dispersions of polyvinylacetate form non-homogeneous films on surfaces at room temperature.Liquid solvents and plasticizers generally are unsatisfactory for aidingin the formation of continuous films since liquid solvents andplasticizers are continuously released from polyvinyl aoetate film whichcauses the ultimate formation of a hard, inflexible material. Further,solid plasticizers have advantage over liquid plasticizers in that theycan be mixed with powdered polyvinyl acetate and transported and storedas dry compositions which are dispersable in water for applicationpurposes. A still further advantage of solid,

water-soluble plasticizers over liquid, water-insoluble plasticizers isthat no aging period is required, e.g., a period of six hours or more,when the plasticizer is incorporated into the compositions.

The following examples will serve to embodiments of the invention.

illustrate specific Example 1 To 50 grams of polyvinyl acetate resinlatex (WC-130, 58.9 percent total solids, Bakelite) there was added 25grams of a solution composed of 15 grams of acetamide and 10 grams ofdistilled water. After the ingredients were thoroughly mixed, a film wascast on glass at room temperature and after it was air-dried a clear,continuous, flexible coating was produced.

Example 2 Example 3 To a portion of finely-divided polyvinyl acetatepowder 1 there was added 10 percent by weight of acetamide, based on theweight of resin, to form a uniform mixture. A quantity of distilledwater was added with stirring to yield a dispersion of 50 percent solidscontent. The dispersion was cast on glass and a clear, continuous,flexible coating was obtained at room temperature.

Example 4 In the manner of Example 1, ethyl carbamate was added to thelatex at a concentration of 5 percent by weight, based on the Weight ofresin. A coating of the latex composition air-dried at room temperaturewas clear, continuous and flexible.

Example 5 In the manner of Example 1, succinimide was added to the latexat a concentration of 10 percent by weight, based on the weight ofresin. A coating of the latex composition air-dried at room temperaturewas clear, continuous and flexible.

Example 6 In the manner of Example 1, succinonitrile was added to thelatex at a concentration of 10 percent by weight, based on the weight ofresin. An air-dried coating of the latex composition on glass was clear,continuous and flexible.

Example 7 In the manner of Example 3, there was added 5 percent byweight, based on the weight of finely-divided resin, of ethyl carbamate.A continuous coating was produced when an aqueous dispersion of thecomposition was cast on glass and air-dried at room temperature.

Example 9 Average particle size of approximately 20p. Composition of97.5% polyvinyl acetate, 1.5% Water and 1.0% of the potassium salt of apolyvinylmethyl ether maleic anhydride c0; polymer (specific viscosityof 0.8-1.2).

In the manner of Example 1, acetamide was added to portions of the latexat concentrations of 5 percent, percent, percent and 30 percent byweight, respectively, based on the weight of resin. Coatings of thecompositions air-dried at room temperature were continuous and flexible.Each of the coatings remained flexible when aged at room temperature forseveral weeks.

Example 1] In the manner of Example 1, tricyanoethyl amine Was added toportions of the latex at concentrations of 10 percent and percent byweight, respectively, based on the weight of resin. Coatings of thecompositions air-dried at room temperature were continuous and flexible.

Example 12 In the manner of Example 1, the solid plasticizers tabulatedbelow were added to the latex at concentrations of 5 percent and 10percent by weight, respectively, based on the weight of resin. Films ofthe compositions were cast and air-dried at room temperature on tinfoil. The tin foil was removed by an amalgamating process and theunsupported resin films were used for tensile strength determinations.

Tensile, lbs./ Percent in. Elongation at Break Control Film (withoutsolid plasticizer). 475 0 Ethyl Carbamate:

57 2, 200 105 107 1,880 280 7 870 75 '7 830 5 5 7 2,830 '7 2, 335 165 572, 600 120 1,880 295 57 3,000 80 0% 1, 900 300 Tricyanoethyl Amine:

Example 13 Percent by Components: Weight Water 26.50 Tamol 731 (2.5%'N.V.*) 1 0.53 Sodium hydroxide (10% N.V.) 0.34

Sodium dispersionof alpha protein (10% N.V.) 2.52 Hubers X-43 2 24.60Atomite 3 12.30 Titanium dioxide 12.30 Foamex 0.01

Percent by Components: Weight WC-l30 (Bakelite polyvinyl acetate latex)12.30 Acetamide (50% N.V.) 8.60

*Non-volatiles.

1 Trademark for a dispersing agent comprising the sodium salt of condened aryl sulfonic acid.

2 China clay.

3 Trademark for mechanically-ground calcium carbonate substantially freefrom particles larger than 15 microns in l i'ii d emark for a mixture ofmodified alkyl esters used as a foam retarder; specific gravity 25/25 C.of 0.96 to 0.97.

The clay was slurried into water and half of the Tamol 731 and all ofthe sodium hydroxide was added. The pigments and the remaining portionof Tamol 731 were then stirred into the mixture. This was followed bythe addition of the protein dispersion and the Foamex and the mixturewas stirred for thirty minutes. Then the latex and the acetamidesolution were added and the total mixture was stirred until smooth.

The composition was applied to a substrate and forcedried for one minuteat a temperature of 93 C. The resulting coating exhibited excellentscrub resistance (no film removal at 2,000 scrub cycles), and no filmwas removed when a piece of Scotch tape was pressed down on the coatingand quickly lifted.

What is claimed is:

1. A substantially dry-blend composition capable of forming continuous,flexible coatings on substrates at room temperature when applied as anaqueous dispersion which consists essentially of finely-dividedpolyvinyl acetate and in admixture therewith about 5 to about weightpercent, based on the Weight of polyvinyl acetate, of succinimide.

2. A process for producing plasticized polyvinyl acetate compositionscapable of forming continuous, flexible coatings on substrates at roomtemperature which comprises dispersing in an aqueous vehicle asubstantially dry-blend composition consisting essentially offinelydivided polyvinyl acetate and in admixture therewith about 5 toabout 60 weight percent, based on the weight of polyvinyl acetate, ofsuccinimide.

3. A substantially dry-blend composition capable of forming continuous,flexible coatings on substrates at room temperature when applied as anaqueous dispersion which consists essentially of finely-dividedpolyvinyl acetate and in admixture therewith about 5 to about 30 weightpercent, based on the weight of polyvinyl acetate, of succinimide.

References Cited by the Examiner UNITED STATES PATENTS 1,844,714 2/1932Carroll et a1. 106-76 2,496,976 2/1950 Barney 260-855 2,530,852 11/1950Bixby 260-34.2

JOSEPH L. SCHOFER, J. NORRIS,

Assistant Examiners.

1. A SUBSTANTIALLY DRY-BLEND COMPOSITION CAPABLE OF FORMING CONTINOUS,FLEXIBLE COATINGS ON SUBSTRATES AT ROOM TEMPERATURE WHEN APPLIED AS ANAQUEOUS DISPERSION WHICH CONSISTS ESSENTIALLY AT FINELY-DIVIDEDPOLYVINYL ACETATE AND IN ADMIXTURE THEREWITH ABOUT 5 TO ABOUT 60 WEIGHTPERCENT, BASED ON THE WEIGHT OF POLYVINYL ACETATE, OF SUCCINIMIDE.
 2. APROCESS FOR PRODUCING PLASTICIZED POLYVINYL ACETATE COMPOSITIONS CAPABLEOF FORMING CONTINUOUS, FLEXIBLE COATINGS ON SUBSTRATES AT ROOMTEMPERATURE WHICH COMPRISES DISPERSING IN AN AQUEOUS VEHICLE ASUBSTANTIALLY DRY-BLEND COMPOSITION CONSISTING ESSENTIALLY OFFINELYDIVIDED POLYVINYL ACETATE AND IN ADMIXTURE THEREWITH ABOUT 5 TOABOUT 60 WEIGHT PERCENT, BASED ON THE WEIGHT OF POLYVINYL ACETATE, OFSUCCINIMIDE.